Hi I am also getting the same error message also upgraded to IE7 and using Sophos Anti Virus...
Acrobat failed to connect a DDE server.
Wow, we upgrade to Sophos Anti-virus as well.
It looks like things are pointing towards Sophos.
Our Cisco VPN clients are having issues connecting back into the office after the upgrade to Sophos.
I've seen 3 cases this past couple of weeks. Users have been using Adobe Reader 9.0, Sophos, and IE 7 without problems. All 3 started getting this error after they went to Reader 9.1.
For the first 2, after I ended all the AcroRd32.exe processes, and had them reboot, I haven't heard back from them since. It's been a few days. For this third one, I just ended the processes so I will have to wait and see if the user calls back. Seems like the problem is with the new 9.1 update.
It look like we found the issue. It was sophos with it's application control. We had to turn off the on-access scanning for the application control policy. Now the PDFs open fine now.
I installed LOGMEIN today and started getting the Fatal Errors:Acrobat failed to connect a DDE server. So, it is not just the Sophos or whatever the previous common denominator seemed to be. How do I fix this?
No solution I am afraid but same problem, running full version of AVG and problem hit immediately after Adobe Reader 9.1 upgrade. Pretty darn sure problem is in the upgrade but the relevant Restore Point was overwritten before I figured it out. Any advice welcome.